Will comet ISON survive its trip around the sun?

AP Photo/NASA, Aaron Kingery<br>
In this photo provided by NASA, Comet ISON shows off its tail on Nov. 19. At the time of this image, Comet ISON was some 44 million miles from the sun – and 80 million miles from Earth - moving at a speed of 136,700 miles per hour.

Something interesting will be happening on Thanksgiving besides conversations around the turkey and college football.

Amateur stargazers and professional astronomers are anxiously waiting to see whether Comet ISON survives its close brush with the sun on Thanksgiving.

If you want to watch a planetary battle on your computer while watching football on the TV, check out NASA's Google+ Hangout called Comet ISON Live from 11:30 a.m. to 1 p.m. on Thanksgiving Day as the comet comes closest to the sun.

NASA is billing it as "Fire vs. ISON: Watch the Epic Battle live."

If it survives, as early as Saturday (after it gets far enough away from the sun) it will rise about 30 minutes before the sun and could be visible looking east-southeast.

And if it survives, the comet could be visible to the naked eye in December. The northern hemisphere will get the best views.

"We have absolutely no idea if ISON will survive past the Sun or not, and how it might look in our December night skies, if it ever gets that far," astronomer Karl Battams wrote on the isoncampaign.org blog Monday afternoon from Kitt Peak in southern Arizona. "This is ground-breaking science unfolding for everyone at the same time and all you need is an Internet connection in order to follow along!"

The comet is a first-time visitor to our solar system from the distant Oort Cloud, and because it was discovered 14 months ago, scientists have had a rare, lengthy opportunity to organize their efforts and study it. More often than not, they have only a few hours to view these "sungrazing" comets before their demise, the isoncampaign.org website explains.

Astronomer Matthew Knight of Flagstaff's Lowell Observatory is a member of NASA's Comet ISON Observing Campaign team of nine scientists who are leading a worldwide effort to study the comet. In his Nov. 5 blog on the campaign's website at isoncampaign.org, he laid out three possibilities for the comet's future:

 It could spontaneously disintegrate before it reaches perihelion (its closest distance from the sun).

 The heat of the sun could vaporize its ice-packed dust and rocks on Thanksgiving, or the sun's gravity could pull it apart.

"Destroyed comets can still be spectacular, though," Knight noted. "Sungrazing Comet Lovejoy, for instance, passed within 100,000 miles of the sun's surface in December 2011. It disintegrated, forming a long tail of dust that wowed observers on Earth."

 The comet survives and provides a show to Earthlings.

"In a 'pie in the sky' scenario, we might be dazzled with a tail spanning half the sky and a coma that remained visible for months, like the sungrazing comet of 1680," Knight wrote.

In a related NASA online article, Knight said he's happy with any of the outcomes.

"Regardless of what happens, we're going to be thrilled," he said. "Astronomers are getting the chance to study a unique comet traveling straight from 4.5 billion years of deep freeze into a near miss with the solar furnace using the largest array of telescopes in history."

As of Monday, scientists were concerned that the comet might be dying because its nucleus seemed to have stopped producing new material.

If it survives, the comet will pass Earth as close as the Great Comet of 1680 (but don't worry, it won't collide with us).

Then the comet is likely to continue on its path out of this solar system and never return.